At the Örnsköldsvik Airport test site in Sweden, PHISHES is advancing the validation of tools and simulation models to assess remediation strategies for soils and groundwater impacted by PFAS contamination.
Located roughly 450 km north of Stockholm, the airport site has been the focus of several environmental studies due to PFAS contamination linked to the historical use of aqueous film-forming foams (AFFF) during fire-fighting training activities until 2008. As a well-characterised and relatively contained site, it provides a valuable framework for exploring which environmental data are needed to evaluate remediation scenarios and support informed policy decisions.
The detailed hydrogeological and environmental datasets available from the site allow modelling approaches developed under controlled conditions to be tested and applied to a real-world case.
Defining scenarios and strengthening model integration
Activities carried out so far have focused on defining realistic remediation scenarios, performing initial parameterization and exploring different model packages. Work has also started on preparing the coupling of different model trains, helping to connect knowledge from pilot-scale studies with real field conditions at Örnsköldsvik.
Testing of the HYDRUS model – a software designed for simulating water, heat, and solute movement in 1D, 2D, or 3D variably saturated porous media – has included conceptual modelling of input parameters and assessment of model discretization. These steps help to ensure that simulations properly reflect site-specific complexities and provide meaningful insights into the behaviour of contaminants and water fluxes under varying conditions. By identifying how different remediation scenarios influence parameters – such as hydraulic conductivity, porosity and recharge – the team is improving its capacity to evaluate long-term outcomes.
Next steps: evaluating fluxes and coupling models
The next phase will focus on evaluating water fluxes and boundary conditions with HYDRUS and MODFLOW models to ensure that water movement and distribution are accurately represented across the study area. Additional analyses will assess PFAS fluxes using HYDRUS-1D/PHREEQC under varying partitioning conditions in both the unsaturated and saturated zones, improving understanding of how these contaminants are retained and transported in the environment.
Results obtained from Hydrus 1D and 2D modelling approaches will be compared to strengthen confidence in the simulations. In parallel, researchers are developing a framework for coupling HYDRUS with MODFLOW. This integrated modelling approach will support a more comprehensive evaluation of remediation scenarios and help inform science-based strategies for managing PFAS contamination.